You should only change Tracks during the last week of your billing cycle. Even though, technically, you can do this "at any time," that is not the best idea. This is an automated system, and because of that, it is best to make changes near the end of your billing cycle to avoid getting double-charged during that month.
This is all you need to know, so you can stop reading now and leave the page if you like!
However . . . for those who want more detail:
How this automated system works:
Whenever you register for any Track, you are charged immediately for a 30 day increment.
If you withdraw from (cancel) a Track, you will continue to have access throughout its 30 day cycle, at which time it will end; but you won't be charged for it again.
Simple, right? So why be careful, here? Because you can cause yourself to get double or triple charged. (What follows will sound like a 5th grade math problem)
Suppose you register for Silver Track.
Now, suppose that 5 days later you decide to upgrade or downgrade. So, you register for a different Track (to replace the first one). You might think, "The system will know how to make an immediate adjustment for the difference in price." Well, that would be nice, but the system does NOT know that. The automated system is not that smart! It thinks in terms of 30 days. So now the system thinks there are two orders for 30 days each, and it will now charge you for this new Track as a new 30 day order. (The system is unable to pro-rate your previous payment or make adjustments.)
Now suppose that 3 days later, you decide to upgrade or downgrade yet again. So you register for a new Track again, to replace the previous one. Technically, you can do this. But the system will have charged you 3 times, each for 30 days.
Now suppose you decide to contact us to "fix" this and refund some money for you. We'll fix it, but we'll charge you for it---maybe even the whole amount you expect to get back. Why? Because it takes us time and effort to fix these things. (We don't want or have time to mess with it any more than you do!)
So here's the 5th grade question:
Q: How can you be smarter than the system? (choose only 1 of the following answers):
1: To avoid this situation, I should only make upgrades/downgrades just before the end of my billing cycle.
2: Or, I should keep making changes all month long and just not worry about it.
The Answer is #1. If you guessed number 2, you should get a tutor.
Hopefully, you understand clearly that you are dealing with an automated system. To avoid problems with it, simply wait until the last 2 or 3 days at the end of the billing cycle before you upgrade or downgrade. (Just don't wait till it runs out.)